1. Field of the Invention
The present invention relates to oral communication and more particularly concerns intelligibility of the human voice in the presence of high ambient noise.
2. Description of Related Art
Public address systems are employed in large areas to make announcements or otherwise orally communicate with a large group of people in the same general location. Frequently the area in which the listeners are located is subject to very high background noise, often of such a level that intelligibility of the desired spoken communication from the public address loudspeaker system is greatly degraded. There are many environments of this type where communication is lost or at least partly lost because high ambient noise level masks or distorts the announcer's voice, as it is heard by the listener. These environments include airports, subway, bus and railroad terminals, aircraft and trains, aircraft carriers, landing craft, helicopters, dock facilities and other noisy places. No one who has attempted to understand a public announcement regarding arrival or departure of a plane or train can fail to appreciate the difficulty of extracting useful information in the presence of such background noise.
Attempts to minimize loss of intelligibility in the presence of high background noise have involved use of equalizers, clipping circuits, or simply increasing the volume of the public address announcement. Equalizers and clipping circuits may themselves increase background noise, and thus fail to solve the problem. Increasing overall level of sound or volume of the public address system does not significantly improve intelligibility and often causes other problems such as feedback and listener discomfort.
Despite the widespread and longstanding recognition of the problem, there has been no solution. Effectively, there is no previously known method for significantly improving intelligibility of public communication, such as public address announcements and the like, that are masked by high ambient noise conditions.
Accordingly, it is an object of the present invention to provide for improved intelligibility of voice communication that would otherwise be degraded by background noise.